Which of the following groups of transition metals is known as coinage metals?

Which of the following elements has the highest number of unpaired electrons in its ground state?

Which of the following ions exhibits a $3d^0 4s^0$ electronic configuration?

The spin only magnetic moment of $Mn^{4+}$ ion is nearly (in $BM$)

What metals are in German silver alloy?

Assertion: Cuprous ion $(Cu^{+})$ has unpaired electrons while cupric ion $(Cu^{2+})$ does not.
Reason: Cuprous ion $(Cu^{+})$ is colourless whereas cupric ion $(Cu^{2+})$ is blue in the aqueous solution.